1,151 results match your criteria: "Lebedev Physical Institute[Affiliation]"

This work considers a solenoid-based magnetic collimation system for improving the efficiency of ion trap loading with ions created by laser ablation. We discuss a physical model of ion beam collimation in such a system, provide qualitative analytical estimates of its collimation characteristics, develop a numerical model of ion collimation based on a test-particle approach, and describe a real experimental setup where the proposed approach is effectively employed to collimate 232Th3+ and 88Sr1+ ions. The experimental results are compared with the results of the performed numerical modeling.

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Coherent spin dynamics of electrons in CdSe colloidal nanoplatelets are investigated by time-resolved pump-probe Faraday rotation at room and cryogenic temperatures. We measure electron spin precession in a magnetic field and determine -factors of 1.83 and 1.

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Precipitation patterns are commonly concentric rings forming in a Petri dish or parallel bands appearing in a test tube (Liesegang phenomenon). The rings frequently consist of a number of convex segments that are separated from each other by spaces devoid of precipitate resulting in small gaps (dislocations). Along these gaps, the so-called zig-zag structures can form, which connect one side of a gap with its opposite side.

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A novel vanadium hydroxide-phosphate, NH VPO OH, was synthesized hydrothermally in V O -NH H PO -citric acid system at 230 °C. It was characterized by XRD, TG-DSC, SEM-EDX, FTIR and NMR spectroscopy. NH VPO OH is isostructural with NH GaPO OH and features edge-sharing chains of VO octahedra.

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Tin-Vacancy (Sn-V) colour centres in diamond have a spin coherence time in the millisecond range at temperatures of 2 K, so they are promising to be used in diamond-based quantum optical devices. However, the incorporation of large Sn atoms into a dense diamond lattice is a non-trivial problem. The objective of our work is to use microwave plasma-assisted chemical vapour deposition (CVD) to grow Sn-doped diamond with submicron SnO particles as a solid-state source of impurity.

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Radiation dermatitis (RD) is one of the most common side effects of radiation therapy. However, to date, there is a lack of both specific treatments for RD and validated experimental animal models with the use of various sources of ionizing radiation (IR) applied in clinical practice. The aim of this study was to develop and validate a model of acute RD induced using proton radiation in mice.

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The first Yb complexes comprising a quinoline-2-carboxylate (quinaldinate, Q) ligand, namely 1D-polymeric [Yb(acac)(Q)] (1, acac is the acetylacetonate (pentane-2,4-dionate) anion) and mononuclear [Yb(acac)(Q)(Phen)] (2, Phen is 1,10-phenanthroline), are reported. The bifunctionality of both complexes as field-induced single-molecule magnets (SMMs) and near IR luminophores has been revealed. The SMM properties of 1 and 2 have been discussed in terms of the geometry and composition of the coordination environment.

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A joint structural and spectroscopic study of simple bis-cyclometataled rhodium(III) and iridium(III) complexes with 2-phenylpyridine and aromatic β-diketones (dibenzoylmethane, benzoylacetone, benzoyltrifluoroacetone, and 2-thenoyltrifluoroacetone) reveals an interplay between the solid-state emission efficiency and crystal packing peculiarities of the complexes. Although the prepared rhodium(III) cyclometalates are isostructural with iridium(III) analogues, different types of π-π interactions are responsible for the aggregation-induced emission (AIE) of the complexes depending on the metal ion. For iridium(III) complexes, pyridyl-pyridyl contacts are essential for AIE because they lower the energy of the emissive metal-to-ligand charge transfer state below that of the non-emissive state located at the ancillary ligand.

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Thin-layer Al/MgF coatings are currently used for extraterrestrial far-UV astronomy as the primary and secondary mirrors of telescopes (such as "Spektr-UF"). Successful Hubble far-UV measurements have been performed thanks to MgF on Al mirror coatings. Damage of such thin-layer coatings has been previously studied under exposure to high-energy electrons/protons fluxes and in low Earth orbit environments.

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We discuss qubit-state superpositions in the probability representation of quantum mechanics. We study probability distributions describing separable qubit states. We consider entangled states on the example of a system of two qubits (Bell states) using the corresponding superpositions of the wave functions associated with these states.

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The acquisition of reliable knowledge about the mechanism of short laser pulse interactions with semiconductor materials is an important step for high-tech technologies towards the development of new electronic devices, the functionalization of material surfaces with predesigned optical properties, and the manufacturing of nanorobots (such as nanoparticles) for bio-medical applications. The laser-induced nanostructuring of semiconductors, however, is a complex phenomenon with several interplaying processes occurring on a wide spatial and temporal scale. In this work, we apply the atomistic-continuum approach for modeling the interaction of an fs-laser pulse with a semiconductor target, using monolithic crystalline silicon (c-Si) and porous silicon (Si).

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A comprehensive study of superconducting properties of underdoped NaFe0.979Co0.021As single crystals by a combination of upper critical field measurements and incoherent multiple Andreev reflection effect (IMARE) spectroscopy is presented.

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Transformation of Nano-Size Titanium Dioxide Particles in the Gastrointestinal Tract and Its Role in the Transfer of Nanoparticles through the Intestinal Barrier.

Int J Mol Sci

October 2023

Department of Veterinary Medicine, Institute of Veterinary, Veterinary-Sanitary Examination and Agricultural Safety, Russian Biotechnological University, Volokolamskoe Highway 11, Moscow 125080, Russia.

In this work, the size transformation of the TiO nanofraction from pharmaceutical grade E171 powder was studied during its transit through the gastrointestinal tract (GIT). It was shown that pharmaceutical-grade TiO powder contained about 0.68% (/) of particles smaller than 240 nm in diameter.

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Article Synopsis
  • Confocal scanning Raman and photoluminescence microspectroscopy is a non-invasive method for analyzing skin tissue biomarkers, specifically used in diagnosing malignant skin tumors.
  • The study found distinct differences in Raman spectra between basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) compared to healthy skin, using various excitation wavelengths (532, 785, and 1064 nm).
  • Two novel wavelength-independent spectral criteria were proposed to differentiate healthy skin from BCC and SCC, achieving over 95% sensitivity and specificity, highlighting its clinical significance in skin tumor diagnostics.
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The production of non-toxic and homogeneous colloidal solutions of nanoparticles (NPs) for biomedical applications is of extreme importance nowadays. Among the various methods for generation of NPs, pulsed laser ablation in liquids (PLAL) has proven itself as a powerful and efficient tool in biomedical fields, allowing chemically pure silicon nanoparticles to be obtained. For example, laser-synthesized silicon nanoparticles (Si NPs) are widely used as contrast agents for bio visualization, as effective sensitizers of radiofrequency hyperthermia for cancer theranostics, in photodynamic therapy, as carriers of therapeutic radionuclides in nuclear nanomedicine, etc.

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This study presents data on the growth rate and frequency of induction of the solid form of Ehrlich's ascites carcinoma (EAC) in mice in the short and long term after inoculation of ascitic cells irradiated ex vivo with a proton beam in the dose range of 30-150 Gy. It was shown that the growth rate of solid tumors after inoculation of irradiated cells ex vivo coincided with the growth of tumors in the control group. The frequency of tumor induction in mice after inoculation of EAC cells irradiated at a dose of 30 Gy was 80%, 60 Gy-60%, 90 Gy-25%, and 120 Gy-10%; at irradiation at a dose of 150 Gy, no tumors appeared during the entire observation period.

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Two- and three-component systems of superdiffusion equations describing the dynamics of action potential propagation in a chain of non-locally interacting neurons with Hindmarsh-Rose nonlinear functions have been considered. Non-local couplings based on the fractional Laplace operator describing superdiffusion kinetics are found to support chimeras. In turn, the system with local couplings, based on the classical Laplace operator, shows synchronous behavior.

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The proximal caudal vertebrae and notochord in thick-toed geckos (TG) (, Gray, 1864) were investigated after a 30-day space flight onboard the biosatellite Bion-M1. This region has not been explored in previous studies. Our research focused on finding sites most affected by demineralization caused by microgravity (G0).

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This study presents a method for fabricating a film-based heating element using a polymer material with an array of intersecting conductive elements embedded within it. Track-etched membranes (TM) with a thickness of 10m were used as the template, and their pores were filled with metal, forming a three-dimensional grid. Due to the unique manufacturing process of TM, the pores inside intersect with each other, allowing for contacts between individual nanowires (NWs) when filled with metal.

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A series of cyclometalated complexes of ruthenium (II) with four different substituents in the aryl fragment of benzimidazole was synthesized in order to study the effect of substituent donation on the electronic structure of the substances. The resulting complexes were studied using X-ray diffraction, NMR spectroscopy, MALDI mass spectrometry, electron absorption spectroscopy, luminescence spectroscopy, and cyclic voltammetry as well as DFT/TDDFT was also used to interpret the results. All the complexes have intense absorption in the range of up to 700 nm, the triplet nature of the excited state was confirmed by measurement of luminescence decay.

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The structure, phase composition, corrosion and mechanical properties, as well as aspects of biocompatibility in vitro and in vivo, of a Zn-1%Mg-0.1%Dy alloy after equal-channel angular pressing (ECAP) were studied. The structure refinement after ECAP leads to the formation of elongated α-Zn grains with a width of ~10 µm and of Mg- and Dy-containing phases.

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Transitions between metastable equilibria in the low-temperature phase of dynamical Ising game with activity spillover are studied in the infinite time limit. It is shown that exponential enhancement due to activity spillover, which takes place in finite-time transitions, is absent in the infinite time limit. In order to demonstrate that, the analytical description for infinite time trajectory is developed.

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We study the sources of intense ultra-high-frequency (UHF) radiation (in the frequency range 1-6 GHz) arising during the development of high-voltage atmospheric discharges. The discharges were initiated in a long discharge gap by applying an approximately 1-MV pulse with positive or negative polarity. By employing a radio registration system based on ultrawideband antennas, we managed to localize the UHF radiation sources in the discharge with centimeter accuracy and investigate their temporal and spatial correlation with the discharge structures.

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Metabolomics reveals that PS-NPs promote lung injury by regulating prostaglandin B1 through the cGAS-STING pathway.

Chemosphere

November 2023

Department of Occupational and Environmental Health, Xiangya School of Public Health, Central South University, Changsha, Hunan Province, 410078, China. Electronic address:

Nanoplastics have been widely studied as environmental pollutants, which can accumulate in the human body through the food chain or direct contact. Research has shown that nanoplastics can affect the immune system and mitochondrial function, but the underlying mechanisms are unclear. Lungs and macrophages have important immune and metabolic functions.

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The spatial spin modulated structure (SSMS) of the cycloid type present in bulk BiFeO prevents the linear magnetoelectric effect. One way to influence this structure is to reduce the crystal size to the nanoscale. Various opinions are circulating in the literature about the effect of nanocrystal size on SSMS, and to investigate this issue, we used a number of methods, with zero-field NMR (ZF NMR) spectroscopy at the forefront.

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